Risk Management of Aircraft Wiring SystemOct. 23, 2003

Wayne BoblittChuck Singer

6th Annual Systems Engineering Conference

Presentation Outline

• NAVAIR Wiring Systems Branch• Wiring Problem/Fleet Metrics• Arc Tracking & Kapton Wiring• Hazardous Risk Matrix and Analysis• Risk Mitigation Approaches

– Training– Selective Rewire– Total Rewire– Arc Fault Circuit Breakers– Apply advanced diagnostic techniques

• Wiring Risk Mitigation Options & Analysis• Conclusions

We Are Responsible For Three ThingsWe Are Responsible For Three Things

1. We Ensure That the Fleet and the OEMs Get Good Parts Maintain Qualified Products Lists (Suppliers) Backed up by Testing. Maintain and Transition Specifications

2. We Ensure Adequate Wiring System Designs and Installations Assess New Aircraft Wiring Installations As Well As Third Party Modifications Evaluate Installations for SOF, Workmanship, Performance and Maintenance Issues Review and Approve Flight Clearance Requests

3. We Ensure Aircraft Wiring System Integrity Throughout Its Life Cycle Monitor and Analyze Data

• Quantify Risk and Recommend Solutions and Options Aging Wiring System Assessments Ensure That Fleet Gets Proper Training Ensure That Wiring Maintenance Manuals Are up to Date Ensure That Proper Tooling is Available Ensure That Technology Solutions Meet Fleet Needs (Arc Fault Circuit Breakers, Diagnostic Systems)

NAVAIR Wiring Systems Branch

Points of Contact

• Wayne Boblitt - Wiring Systems Branch Head– (301) 342-0808

• David Harrell - Engineering/IPT Lead– (301) 342-0813

• Jerome Collins - Science and Technology Lead– (301) 757-0868

• Pat Merrill - Wiring Systems Assessment Team Lead– (301) 342-0822

• Mike Peppas - QPL Lead– (301) 342-0857

NAVAIR has 45 people who work wiring.

Presentation Outline

• NAVAIR Wiring Systems Branch• Wiring Problem/Fleet Metrics• Arc Tracking & Kapton Wiring• Hazardous Risk Matrix and Analysis• Risk Mitigation Approaches

– Training– Selective Rewire– Total Rewire– Arc Fault Circuit Breakers– Apply advanced diagnostic techniques

• Wiring Risk Mitigation Options & Analysis• Conclusions

Wiring Problem*** 30 months of fleet data ****• 2.5 electrical fires/month - Lost 2

aircraft due to electrical fires• Averaging 1400 mission aborts/year

(540 in-flight aborts/year)• 1-2M operational man-hours/year

spent troubleshooting/repairing wire problems

• Spending $94M/Year due to false equipment removals across the fleet caused by external wiring problems

Aircraft Wiring is the number 2 safety concern of the fleet. Source: 2002 Avionics OAG

Short circuit, unspecified cause (includes arcing incidents)18%

Failure due to corrosion 5%

Loose connection 4%

Unspecified failure 6%

Connector failure 9%

Chafed wire insulation leading to short circuit and/or arcing 37%

Insulation failure3%

Broken wires11%

Crossmating 2%

Short due to corrosion 1%

Miswire 1%

Other 1%

Circuit breaker failure 2%

Metrics and Wire Failure Modes

Safety Data

Quarterly MetricsInventory

Flight Hours

Readiness (NMC)

Availability (Aborts)

Safety (Mishaps)

Reliability (MTBF)

Maintainability (MMH)

Supportability (MFHBCC)

O&S Costs (M&S Costs)

Effectively 125 Non Mission Capable Aircraft/Year Due to Wiring

Presentation Outline

• NAVAIR Wiring Systems Branch• Wiring Problem/Fleet Metrics• Arc Tracking & Kapton Wiring• Hazardous Risk Matrix and Analysis• Risk Mitigation Approaches

– Training– Selective Rewire– Total Rewire– Arc Fault Circuit Breakers– Apply advanced diagnostic techniques

• Wiring Risk Mitigation Options & Analysis• Conclusions

Aromatic Polyimide Insulated Wire Arc Tracking

Aromatic Polyimide Insulated Wire Chafing

Flaking Aromatic Polyimide Insulated Wire

Aromatic Polyimide Insulated Wire /Moisture Induced Arc

Presentation Outline

• NAVAIR Wiring Systems Branch• Wiring Problem/Fleet Metrics• Arc Tracking & Kapton Wiring• Hazardous Risk Matrix and Analysis• Risk Mitigation Approaches

– Training– Selective Rewire– Total Rewire– Arc Fault Circuit Breakers– Apply advanced diagnostic techniques

• Wiring Risk Mitigation Options & Analysis• Conclusions

Hazardous Risk MatrixCATASTROPHIC (1) CRITICAL (2) MARGINAL (3) NEGLIGIBLE (4)

FREQUENT (A) = or > 100/100K flt hrs

1 3 7 13PROBABLE (B)

10-99/100K flt hrs 2 5 9 16OCCASIONAL (C) 1.0-9.9/100K flt hrs 4 6 11 18

REMOTE (D) 0.1-0.99/100K flt hrs 8 10 14 19IMPROBABLE (E)

= or < 0.1/100K flt hrs 12 15 17 20

PMA Acceptance

11-17 LOW SAFETY RISK

IPT / FST / SSWG Acceptance

6-10 MEDIUM SAFETY RISK 18-20 VERY LOW SAFETY RISK

Severity is the worst credible consequence of a hazard in terms of degree of injury, property damage or effect on mission defined below:

Catastrophic - Class A ( damage > $1M / fatality / permanent total disability)Critical - Class B ($200K < damage < $1M / permanent partial disability / hospitalization of 5 or more personnel)Marginal - Class C ($10K < damage < $200K / injury results in 5 or more lost workdays)Negligible - All other injury/damage less than Class C

Probability of occurrence for discreet events may replace Frequency based upon the chart below:

S E V E R I T Y

FREQUENCY

HAZARD CATEGORIZATION

UNACCEPTABLEACCEPTABLE WITH REVIEW

ASN (RD&A) / Fleet Acceptance

UNDESIRABLEACCEPTABLE

WITHOUT REVIEW

1-5 HIGH SAFETY RISK

PEO / AIR-1.0 Acceptance

Age Distribution of One Aircraft Type with Kapton Wiring“Incomplete Data”

0

2

4

6

8

10

12

14

16

18

20

0

250

500

750

1000

1250

1500

1750

2000

2250

2500

2750

3000

3250

3500

3750

4000

4250

4500

4750

5000

5250

5500

5750

6000

TSN (hours)

Qu

an

tity

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

Pe

r P

art

Pro

ba

bil

ity

of

Fa

ilu

re

Total Aircraft of one Type with Kapton

Reported Fire & Arc Failures

Reported Kapton Failures

PPOF of Kapton Fire and Arc Failures

PPOF of All Failures due to Kapton

All Failures due to Kapton

Kapton Fire and Arcing Failures Only

3K 4K

• Increase Training - Focus on Wiring Care and Maintenance

• Perform Selective Rewire

– Fleet has responded with a prioritized list of harnesses.

($9M to fabricate).

– NADEP is gathering the information to support a rewire

effort.

• Perform Total Rewire ($1M/Aircraft)

• Use Arc-Fault Circuit Breakers

• Apply Wiring Diagnostics Technology When

Available.

Risk Mitigation Approaches

Presentation Outline

• NAVAIR Wiring Systems Branch• Wiring Problem/Fleet Metrics• Arc Tracking & Kapton Wiring• Hazardous Risk Matrix and Analysis• Risk Mitigation Approaches

– Training– Selective Rewire– Total Rewire– Arc Fault Circuit Breakers– Apply advanced diagnostic techniques

• Wiring Risk Mitigation Options & Analysis• Conclusions

Wiring Inspection Training

NAVAIR has developed wiring inspection course.

Class Approach:• Explain common problems AIR-4.4.4.3 observes Fleet wide. Clamping, evil Zip-

ties, wire routing, chafing, hardware use, connector types/proper stowage, combat repairs.

• Provide Customized presentation of squawks found on squadron aircraft and presented how they were found. Note: Aircraft was assessed on-site prior to the class to gain photos. Interactive presentation, “Here is a condition we found. What do you think is wrong here?

• Explain reasons for specifications and how they pertain to their aircraft. “Who the !!@@??%&# designed this stuff, anyway?”

• Provide hands-on training. On-Acft training allowing participants to practice some inspection techniques.

• Encourage proactive approach, find problems during Acft down times, look around after maintenance is complete.

Training

Training – Option 1

Training – Option 1

Power Feeders Chafing on Hardware

Electromagnetic Interference (EMI)

Ungrounded Shields Acting as Antennas

Grease covered over braided wire bundle lying on flight control cable.

Clamped to hydraulic line for primary support and to take out slack.

Cut Wires left in shorting blocks

Wire Chafing on Clamp Hardware

POWER FEEDERS AGAINST ADJACENT METAL BRAIDED FUEL LINE

Just in time manufacturingManufacturing self-inspect

Joint Combat Information Terminal InstallationPanel Screw Will Contact Flight Control Harness

Overheated Terminal Lugs

Wrong Terminal LugsImproper CrimpsUnsupported Wire TypeWrong Wire SizesImproperly Installed CBs

Wiring System AssessmentsWiring System Assessments

• 30%-60%-90% In-Process Assessments

– In-Process Development, Production and Modification Monitors

• Final/Acceptance Inspections

• Safety Inspections

• DT and INSURV Trials

• Aging Aircraft Condition Inspections

• 30%-60%-90% In-Process Assessments

– In-Process Development, Production and Modification Monitors

• Final/Acceptance Inspections

• Safety Inspections

• DT and INSURV Trials

• Aging Aircraft Condition Inspections

• Installation of Electrical/Electronic Wiring

• Installations of Electrical/Electronic Equipment

• Electrical Power Distribution Circuit Protection

• Wiring Terminations and Connectors

• Bonding, Grounding and Shielding

• Interference With Structures, Lines and Mechanical Systems

• Identification of Wiring and Equipment

• Consistency in Installations

• Workmanship Practices

• FOD Control

• Installation of Electrical/Electronic Wiring

• Installations of Electrical/Electronic Equipment

• Electrical Power Distribution Circuit Protection

• Wiring Terminations and Connectors

• Bonding, Grounding and Shielding

• Interference With Structures, Lines and Mechanical Systems

• Identification of Wiring and Equipment

• Consistency in Installations

• Workmanship Practices

• FOD Control

Assessment FocusAssessment Focus

Class Comments

“Seeing the slides of our own aircraft really hit home”

“Should be mandatory training”

“This training gave a different way to inspect aircraft. Proper use of this training will only better this squadron”

“Slide presentation was very effective, especially slides used on squadron aircraft that was previously inspected (Not some old slides taken years ago)”

“I need to go back and train the rest of the division”

AF Sergeant: 90% of my wiring problems can be solved with training.

Presentation Outline

• NAVAIR Wiring Systems Branch• Wiring Problem/Fleet Metrics• Arc Tracking & Kapton Wiring• Hazardous Risk Matrix and Analysis• Risk Mitigation Approaches

– Training– Selective Rewire– Total Rewire– Arc Fault Circuit Breakers– Apply advanced diagnostic techniques

• Wiring Risk Mitigation Options & Analysis• Conclusions

Total Aircraft Re-WireReduces additional failures but does not eliminate them

Cost $1M per aircraft

0100 02 03 04 07 08

Arc Fault Circuit BreakerDevelopmental Timeline

05 06Fiscal Year

Transport Aircraft

InstallFlight Test

Prod.Development

ONR/FAA/AAIPTComponent Impr Program

Fighter/Helo/Patrol A/C

Ground Test

FlightTest

Prod.Lab Test

BeginDevel

MS24571MS24571

MS3320 MS3320

Current Status:

•Flying in C-9 and 727

•Available in FY05

• MS14105 & MS24571 Specs. will be voted on October, 2003

• QPL to follow in Oct.

•Texas Instruments

•Eaton

•Ametek

Presentation Outline

• NAVAIR Wiring Systems Branch• Wiring Problem/Fleet Metrics• Arc Tracking & Kapton Wiring• Hazardous Risk Matrix and Analysis• Risk Mitigation Approaches

– Training– Selective Rewire– Total Rewire– Arc Fault Circuit Breakers– Apply advanced diagnostic techniques

• Wiring Risk Mitigation Options & Analysis• Conclusions

TEST SYSTEMSTEST SYSTEMS(MIL-STD-810 EXPLOSIVE ENVIRONMENT)(MIL-STD-810 EXPLOSIVE ENVIRONMENT)

IMPLEMENTATIONIMPLEMENTATION•O-LEVELO-LEVEL•I-LEVELI-LEVEL•DEPOT- DEPOT- Starting PointStarting Point

Standing Wave Standing Wave Reflectometer - With Plain Reflectometer - With Plain Text DisplayText Display

Ruggedized LaptopRuggedized Laptop

Test Box/Expansion UnitsTest Box/Expansion Units

Smart wiring is the embedding of intelligence and sensors in the wiring system to manage the health of the wiring

SMART WIRING FOR AIRCRAFTDescription of Technology

Mission Computer/Test Set and Associated Software

Applicable to Conventionaland Organized Wiring Systems

To SIC

Sensors embedded or attachedto wiring system components

Rules

Info

Intelligence includes SIC, FFT chip, FDR circuitry, algorithms and

wiring system interface

Wiring Integration Unit (WIU)

SmartConnector

Smart Wiring Harness

SmartWIU

Connector

0100 02 03 04 05 06

Development Flight Test

FLC Study

Wiring Diag. SBIR

Single WireBreadboard

Detection Technology for Insulation Failures

USAF SBIRCo-processor development

Smart Connectors* ‘Hockey Puck’ connector saver* Flight hardware processor/sensor development

ONR 6.3 EffortONR 6.2 Effort

SICEMD/TransitionLead: P-3, PMA-290AAdditional Retrofits: F/A-18, EA-6B, F-14,

AV-8B, V-22, JSF

SMART FIBER OPTIC OVERBRAID

Presentation Outline

• NAVAIR Wiring Systems Branch• Wiring Problem/Fleet Metrics• Arc Tracking & Kapton Wiring• Hazardous Risk Matrix and Analysis• Risk Mitigation Approaches

– Training– Selective Rewire– Total Rewire– Arc Fault Circuit Breakers– Apply advanced diagnostic techniques

• Wiring Risk Mitigation Options & Analysis• Conclusions

Option Action Cost To Implement Continued AC costs NMC Aircraft

1 None $0M $8M/yr increasing to $16M/yr 8 increasing to 16

2 Total Re-wire $150M $8M/yr 8 increasing to 12 leveling off at 8

3 Selective Re-wire (SRW) + AFCB $36.3M $9M/yr 8 increasing to 10

4 SRW, AFCB, Off BWD $41.3M $3.5M/yr 8 decreasing to 7

5 SWR, AFCB, Off BWD, On BWD $48.3M $2M 8 decreasing to 4

Wiring Risk Mitigation Options

Recommend Funding for Option 5

Cost/NMC AC Years/Aborts vs. Wiring Options Over Ten Years

0

100

200

300

400

500Wiring Options

Co

st

(M$

)/N

MC

AC

Yea

rs/ A

bo

rts

Total Cost (M$) 132 254.3 148.8 143.1 135.5

Total NMCAircraft Years

132 104 90 75 66

Total Aborts 483 379 410 374 312

1 2 3 4 5

HRI Rating After

Implementation 4,5 14 6 10 14

1. None

2. Total Rewire

3. Selective Rewire (SWR) + AFCB

4. SWR+AFCB+Off Board Diagnostics

5. SWR+AFCB+Off/On Board Diagnostics

Presentation Outline

• NAVAIR Wiring Systems Branch• Wiring Problem/Fleet Metrics• Arc Tracking & Kapton Wiring• Hazardous Risk Matrix and Analysis• Risk Mitigation Approaches

– Training– Selective Rewire– Total Rewire– Arc Fault Circuit Breakers– Apply advanced diagnostic techniques

• Wiring Risk Mitigation Options & Analysis• Conclusions

PlatformKapton Wiring Deterioration

• Hazard Description: Deterioration of Kapton™ wiring insulation causes wire to wire shorting and arcing resulting in fires, loss/degradation of AFCS, erroneous instrument readings, power surges, failure of aircraft subsystems

• HRI: 2C (6) Medium Risk

• Current Mitigation:– Fleet replacement of damaged wiring at O/I-

Level– Replacement of damaged wiring at SDLM

• Final Resolution:– Plan:

• Short Term: Training. Wiring team inspection of aircraft and development of inspection training program for fleet.

• Mid Term: Targeted prioritized wire harness replacement. Depot field teams & SDLM replacement of critical wiring harnesses. Depot currently reviewing TYCOM/Fleet wiring prioritization survey. Plan for replacement still to be worked out.

• Long Term: Removal of Kapton™ wiring from all aircraft during SLEP. AFCB, Off board and On-Board Diagnostics Funding Needs to be POMed.

– Residual Risk:• Short Term: Potentially reduce frequency of

occurrence (remains medium risk).• Mid Term: Reduction in frequency of

occurrence (likely to remain medium risk).• Long Term: Elimination of hazard.

CATASTROPHIC (1) CRITICAL (2) MARGINAL (3)

FREQUENT (A) = or > 100/100K flt hrs

1 3 7PROBABLE (B)

10-99/100K flt hrs 2 5 9OCCASIONAL (C) 1.0-9.9/100K flt hrs 4 6 11

REMOTE (D) 0.1-0.99/100K flt hrs 8 10 14IMPROBABLE (E)

= or < 0.1/100K flt hrs

S E V E R I T Y

FREQUENCY

HAZARD CATEGORIZATION

Any Questions?